1. Field of the Invention
The present invention refers to a tool-changing mechanism for a metal-forming press, e.g. a bending or an edging press, and an arrangement comprising a metal-forming press and a tool-changing mechanism.
2. Brief Description of the Prior Art
Metal-forming presses are normally provided with exchangeable tool sets. Each tool set comprises at least one upper tool or punch and one lower tool or die. For producing a workpiece or for carrying out a specific bending step at a workpiece, the punch and the die must be adapted to one another. When a new workpiece is to be produced, the punch and the die are both exchanged simultaneously. The associated tools, i.e. punches and dies, have been stored in pairs in a rack away from the press up to now. When the tools are to be exchanged, an operator takes them out of the rack and positions them at a tool changing position in front of the press. Especially in the case of big and heavy tools, the transport to the press as well as the positioning of the tools in the press is difficult. In edging presses, for example, where the punches and dies have lengths of up to 800 mm, said tools must separately be moved to their insertion position, aligned parallel to the respective holder of the press and inserted into said press.
3. Summary of the Invention
In comparison with this prior art, it is the object of the present invention to provide a tool changing mechanism and an arrangement comprising a metal-forming press and a tool-changing mechanism permitting a simple and rapid exchange of tools.
This object is achieved by a tool changing mechanism for a metal-forming press, which comprises a circulating means provided with a plurality of reception means for holding forming tools and which is adapted to be set up beside the metal-forming press, wherein, at a tool changing position, tools are adapted to be transferred from said tool changing mechanism to said metal-forming press or from said metal-forming press to said tool changing mechanism. In this way, a plurality of tool sets each comprising a punching tool, e.g. a punch, and an associated countertool, e.g. a die, can be stored in a common device and they can be supplied rapidly and easily from said device to a press, e.g. an edging press. A complicated positioning of the heavy tools relative to a press by hand is no longer necessary. The tools can be inserted into the metal-forming press and into the tool changing mechanism, respectively, (straight-line tool changing movement).
According to an advantageous further development of the present invention, the tool changing mechanism comprises a movable, endless traction-means drive, which is provided on a frame, and reception means for receiving punching tools as well as reception means for receiving countertools associated with the respective punching tools, said reception means being attached to the traction-means drive. Said reception means are arranged such that a respective punching-tool reception means and a respective countertool reception means, which are used for receiving a punching tool and the associted countertool, follow one another on the traction-means drive. Due to the fact that the reception means for the associated tools are arranged in immediate succession, punching tools and countertools can be exchanged simultaneously or in quick succession, without any renewed complicated fetching being necessary for transporting the second tool to the tool changing position. The successive arrangement on the traction means drive additionally permits the tool changing mechanism to be constructed such that, when arranged at the side of a press, said tool changing mechanism will be flush with the front side of said press so that the operating space at the side and in front of the press will not be restricted. This is particularly advantageous with regard to presses in which very large sheet-metal parts are processed.
According to an advantageous further development of the present invention, the punching-tool reception means and the countertool reception means of each pair of reception means are attached to the traction-means drive in equally spaced relationship with one another. The space is chosen with regard to the position of the tool holders in a press at its position of rest. Hence, the sequence of tool changing steps is reproducable for each pair of reception means and the tools attached to said reception means.
The reception means are preferably pivotably coupled to the traction-means drive. Especially when the traction means drive is arranged vertically--this mode of arrangement being expedient for space-saving reasons--this will prevent the formation of strong bending forces in the reception means when said reception means are moved along the deflection route of the traction means drive.
In accordance with a further advantageous embodiment of the present invention, a position detection device is arranged on the frame for detecting the position of a reception means relative to a predeterminable tool-changing position. This ensures that the traction means drive, which can be driven manually or by a motor, can be stopped precisely at the correct point of the tool changing position. The tool changing operation can, in addition, be automated in this way; for this purpose a suitable control means can be provided, said control means being used for controlling motion devices, e.g. slide members, for loading and unloading the reception means, said motion devices being provided e.g on the frame or on the individual reception means themselves.
According to a further advantageous embodiment of the present invention, at least one storage facility is attached to the traction-means drive for holding punching tools and/or countertools, the tools being adapted to be inserted into and removed from said storage facility in the longitudinal as well as in the transverse direction thereof. These storage facilities are particularly suitable for accommodating a plurality of small or short tools. If necessary, these tools can be removed from the storage facility by hand, and combined so as to form a set of tools which is then pushed into a punching-tool reception means or countertool reception means. The storage facilities can be arranged on the traction means drive at arbitrary distances from one another as long as the associated reception means pairs are not impaired by this arrangement.
The object referred to at the beginning is also achieved by an arrangement comprising a metal-forming press and a tool-changing mechanism, wherein the tool-changing mechanism is set up directly beside the metal-forming press. At the tool changing position, the tools can, consequently, be pushed directly and without further positioning measures out of the tool changing mechanism and into the press. This can be done manually as well as automatically. Preferably, the press is provided with a holder for punching tools and a holder for countertools, said holders being, at a position of rest of the press, located at a distance from one another which corresponds to the distance between a punching-tool reception means and the associated countertool reception means at a tool-changing position, the respective holders and reception means being in alignment with one another. The punches and the dies can efficiently be exchanged in this way.
For the use of already existing tools with the tool changing mechanism according to the present invention, adapters can be attached to holders, said adapters having, in turn, attached thereto these tools such that said tools are slidable in the longitudinal direction of the respective holder. This permits also the use of two-part tools consisting of an upper and a lower part. For this purpose, the tool changing mechanism and the traction means drive, respectively, have a second tool-changing position, which is displaced relative to a first tool-changing position by a displacement length. Said displacement length corresponds to the thickness or rather the height of the lower part so that at said second tool changing position only the tool in question can be transported into the associated holder of the press.
In accordance with a preferred embodiment, a tool-changing mechanism is arranged on either side of the press. This ensures that, simultaneously with the insertion of a new tool into the press, the tool contained in the press can be transported into the opposite tool changing mechanism, whereby the efficiency of the tool changing operation will be increased still further.
In the case of particularly long presses, it is also possible to arrange several juxtaposed tool-changing mechanisms in an in-line arrangement so that the reception means of the individual tool-changing mechanisms are in alignment with one another at the tool-changing position.